This invention relates to adapting drill pipe for use in the oil, gas, and geothermal drilling industries for power and data transmission. More particularly, this invention relates to providing a repeatable reference for positioning and tuning connectors, transducers, and sensors along the drill string and within the drill pipe joint.
The need for acquisition and bidirectional transmission of power and data along the drill string has been recognized for more than half a century, and as exploration and drilling technology have improved, this need has become more and more an imperative in the industry for successful oil, gas, and geothermal well production. However, despite a plethora of literature in this area, the only system to gain commercial acceptance uses pressure impulses transmitted through the drilling fluid as a means for data communication. The chief drawbacks to this system are that the data rate is very slow, less than 10 baud; the system is very complex and expensive; the results are inconsistent; and range of performance is limited. It appears that the other proposed systems have not gained commercial acceptance due to the unique characteristics of the drill pipe tool joint. The following patents exhibit some of the relevant systems proposed to accomplish this most critical task.
U.S. Pat. No. 3,696,332, incorporated herein by this reference, teaches the use of an electrical conductor extended along the interior of each pipe and connected to an annular groove within the pipe joint.
U.S. Pat. No. 3,930,220, incorporated herein by this reference, teaches an acoustic system using repeaters along the drill string to prevent the loss of the signal being transmitted.
U.S. Pat. No. 4,548,431, incorporated herein by this reference, teaches a double shouldered tool joint. The tool joint has both internal and external makeup shoulders. The pin and box are dimensioned so that box face contacts the external shoulder while there is still a clearance the pin face and the internal shoulder. This joint is strengthened against the additional torque that may be encountered downhole when the bit or drill pipe gets stuck.
U.S. Pat. No. 4,807,781, incorporated herein by this reference, is another patent that teaches a telemetry system. Sensors are disclosed that measure such parameters as pressure, temperature, salinity, direction of well bore, bit conditions, as well as the standard well logging parameters. The sensor outputs are converted to a digital form and stored until called for from the surface. Transmission is accomplished by low frequency modulation of a carrier wave in the 1-30 hertz range. The system, including periodic repeaters, is positioned within the bore of the drill pipe without substantially decreasing the clearance for mud flow.
U.S. Pat. No. 4,095,865, incorporated herein by this reference, teaches the use of a conduit deployed within the drill pipe as a conveyance for the insulated conductor and means for attaching the conduit to the pipe wall.
U.S. Pat. No. 4,215,426 teaches a system in which wiring extends through the drill pipe employing magnetic coupling between the pipe sections. The use of signal enforcers is also taught. Power transmission is achieve by means of an acoustic power generator and a means for converting the acoustic wave to a DC voltage.
U.S. Pat. No. 4,220,381, incorporated herein by this reference, teaches the use of a conductor wire in each pipe section connected to electrodes that are exposed to the drilling fluid in each joint. A high voltage is used to hop the current across the joint and thereby provide and link between each pipe section.
U.S. Pat. No. 4,445,734, incorporated herein by this reference, teaches the use of a wire secured within the pipe by a liner. The wire is connected to annular contacts at each joint. The contact mechanism includes a means for wiping the surfaces of the contacts and of exerting pressure on the contacts in order to ensure efficient signal transmission.
U.S. Pat. No. 4,884,071, incorporated herein by this reference, teaches the use of a Hall Effect coupler. A self-contained power supply is located at each joint and coupled to the Hall Effect device sending and receiving units. A conductor wire, shielded by a conduit, extends along the pipe bore and connects couplers at each end of the pipe.
U.S. Pat. No. 5,568,448, incorporated herein by this reference, teaches the use of an ultrasonic wave that is propagated through a propagation medium. An acoustic waver receiver converts the wave to an electric signal.
U.S. Pat. No. 6,041,872, incorporated herein by this reference, teaches the use of a disposable cable deployed along the bore of the drill string. It is deployed from a spool at the bottom of the drill string and fed out as the drill pipes are added. When pipes sections are removed, the cable is cut off and disposed of. A data transmission device is connected to the cable. The cable may be suitable for electromagnetic or fiber optic communications.
U.S. Pat. No. 5,908,212, incorporated herein by this reference, teaches a double shouldered tool joint capable of sustaining high torque. The disclosure identifies a relationship between the cross-sectional areas of the nose section of the pin end and the counter bore section of the box end. The sum of these two areas are correlated with cross-sectional area of the joint wall adjacent the internal shoulder of the box end.
U.S. Pat. No. 6,057,784, also incorporated herein, discloses another combination electromagnetic mud impulse system. Data from sensors at the bit is transmitted by means of an electromagnetic wave to a receiver that converts the wave into a pressure pulse in the drilling fluid for transmission up hole.
What is needed then is a tool joint that provides a repeatable reference for precise positioning and tuning of connectors, sensors, and transducers disposed within the tool joint and at locations along the drill string.